Industrial water systems exist so that necessary chemical, mechanical and biological processes can be conducted to achieve the desired outcome of the process. The use of inert fluorescent tracers in industrial water systems is well-known in the art; see U.S. Pat. No. 4,783,314 Fluorescent Tracers-Chemical Treatment Monitors. In this patent, the fluorescent signal of the inert fluorescent tracer is used to determine how much inert fluorescent tracer is present, and by knowing the amount of inert fluorescent tracer that is present it is possible to determine the amount of treatment product that is present in the industrial water system. If the amount of treatment product that is present is not what is desired then the feed rate of treatment product or other operating parameters of the industrial water system can be adjusted to provide the desired amount of treatment product.
Inert fluorescent tracers are used in boilers; see U.S. Pat. No. 5,041,386 Concentration Cycles, Percent life Holding Time and Continuous Treatment Concentration Monitoring in Boiler Systems by Inert Tracers.
Inert tracers are required in order to conduct the methods described and claimed in these and other patents. Known fluorescent tracers, such as 1,5-naphthalenedisulfonic acid, disodium salt and 1,3,6,8-pyrenetetrasulfonic acid, tetrasodium salt are commercially available from Ondeo Nalco Company, Ondeo Nalco Center, 1601 W. Diehl Road, Naperville Ill. 60563, (630) 305-1000.
Inert tracers are typically defined as those tracers that have a detectable fluorescent signal that does not change more than 10% in the presence of water and the other ingredients in the water of an industrial water system. While water is obviously the major component of an industrial water system there are typically other materials present in an industrial water system. These can include anything from innocuous materials all the way to highly reactive, oxidizing biocides. It is difficult therefore, to identify and use inert tracers for all known industrial water systems. Thus, it is always desirable to identify, test and confirm the use of new materials as inert fluorescent tracers.